| The pest is a big obstacle affecting the product of peach. To improve the level of harnessing the pest economically,enrich the content of community ecology and prompt the subject to develop,this study was carried out on the base of former studies. In this study ,several analytic methods,such as geostatistics,grey system theory and method,etc.,were applied,and the dynamics of arthropod community,the regulation of interactions between Erythroneura swdira(Distant) and its nature enemies were studied. The results were as follows:The arthropod community was divided into four sub-communities:phytophages,predators,parasitorids and neutralities by the standard of nutrition and hunting. The structures and dynamics of arthropod community and different sub-communities were analyzed by using a number of community parameters. The results indicated that there were 55 species of arthropod belonging to 37 families,including 28 species of phytophages representing 18 families;22 species of predators representing 14 families;3 species of parasitorids representing 3 families;2 species of neutralities representing 2 families in peach orchards. The relative abundance of phytophages and predators were 0.953367 and 0.O46188 respectively. So it can be seen that the phytophages dominated the arthropod community in peach orchards. The dominant concentration of phytophages was 0.980648,larger than that of predators(0.886292) and parasitoids(0.420000). The other parameters such as diversity index(H ) and diversity index (Hill) including NI ,N2 ,indicated the same trends,showing in the order :predators sub-community > arthropod community > phytophages sub-community.The shifting trend of the individual number of phytophages was similar to the arthropod community. Both trends had two peaks that occurred at similar time.This indicated that the individual number of arthropod community was influenced mainly by phytophages.Studies on the temporal niche breadth and overlap of Erythroneura sudra and its natural enemies indicated:Erythroneura sudra appeared in all time stages of the year. But,as to the individual,there were big differences between each time stages and this resulted in a low niche breadth index.For the use of insecticide,the individual number of arthropod community and every sub-community all had definite reduction,especially the phytophages.Systematic studies on temporal and spatial dynamics of important arthropod indicated that the dominant species of pest,insect natural enemies,spider natural enemies were Erythroneura sudra,P.Japonicola,E.graminicola respectively. The Erythroneura sudra population fluctuation showed two peaks and the first one occurred in middle May,the second one occurred from middle July to the end of September. The spatial pattern of Erythroneura sudra and E.graminicola were of aggregated type.Based on the systematic surveys in peach orchards,the structures of pests-natural enemies community and their seasonal dynamics were analyzed by the methods of Principal Component Analysis (PCA),optimal sorting and Fuzzy Cluster Analysis .The results showed that they can be distinctly classified into 4 types and had obvious main factors and temporal patterns.The relationships between the number of natural enemies and Erythroneura sudra population size and the relational grade of various natural enemies to ideal dominant natural enemies were analyzed with grey system theory and method. The result was that E.graminicola was the major natural enemy affecting Erythroneura sudra.The spatial construction and distribution of Erythroneura sudra and E.graminicola at different period of the second peak stage of the Erythroneura sudra population fluctuation were studied by geostatistics. The result was that the semivariogram of Erythroneura sudra was described by spherical model,showing an aggregated spatial arrangement,the range was 25.70-37.20m. Thesemivariogram of E.graminicola was fitted by spherical model too,also showingan aggregated spatial arrangement,its range was 25.10-44.10m. Th... |
PDF Full Text Request